I used bleach, ( bleach and urine make a lot of ammonia) , I rinsed it off and then put down huge boxes of baking soda spread on the floor and let it dry and them broomed off.I used gallons of peroxide I bought from a beauty supply place and poured that peroxide full strength on the floor and let it sizzle.. it helped open up the pours in the concrete so the ammonia from the urine would neutralize. 

When mixed with water, it becomes concentrated hydrogen peroxide.

Go over with a spray bottle filled with hydrogen peroxide and water or bleach and water (the hydrogen peroxide is better at permanently dealing with the issue), spray, wait, show them it's gone. 

@Kenneth LaVoie Cat urine is terrible but here is how Ive gotten rid of the odor and its literally such a cheap dumb thing. 1 part hydrogen peroxide, 1 part baking soda, and a little bit of dawn dish soap.

They use hydrogen peroxide then dry and encapsulate with a clear spray paint.

Actually because of Envirotabs, Slick 50, fuel line magnet, tornado, hydrogen generator, and other products I've bought, my fuel tank actually fills as I drive.

I have also read to use a mixture of hydrogen peroxide and boric acid.Not sure what to do at this point.

The two most common elements in the Universe are Hydrogen .... and stupidity"

If the problem is to remove sulfide compounds, and I've found mention of "carbon disulfide, carbonyl sulfide, hydrogen sulfide, and strontium sulfate (trace levels" as the possible culprits in this drywall, then removing them is a somewhat understood process.

Hydrogen sulfide is toxic but may not be a health hazard.